Method for making coffeee



Jan. 4, 1944. M. N. STATES METHOD FOR MAKING COFFEE Fiie d Dec. 16', 1939 INVENTOR ATTORNEYS M AM jnms/mzzmams I Patented Jam 4,

METHOD ron MAKING some Marshall N. States, Evanston, Ill., assignor to Robert C. Brown, In, Highland Park, 111., as

. trustee Application December is, 1939, Serial No. 309,585

7 Claims.

- This invention relates to a method of preparing coffee and similar beverages and to an apparatus suitable for use in the process.

It has been well-known for years that at least some of the substances providing coflee with its characteristic flavor andaroma are volatile in nature and subject to undesirable changes if exposed to air for any considerable period of time. Manufacturers, recognizing this fact, have egercised great care in packing their coilee to in-- sure its arrival in proper condition. However, even when properly prepared coflees are used, cofiee brewers now in use are usually unable to retain in the beverage the full value of fiavor and aroma contained in the coffee itself, as they expose the solution containing the aroma giving and flavoring substances to the air at elevated temperatures for considerable periods of time,

thereby boiling oil or-evaporating the materials most desirable in the finished product.

Therefore, an object of this invention, is to provide a method whereby coflee and similar beverages may be prepared without substantial loss of flavoring and aroma imparting substances.

Another object is to provide an a'pparatussuitable for use in my process in which any reasonable amount of beverage may be prepared regardless of the capacity of the container used.

Further objects and advantages of my invention will become apparent from the following description, and the accompanying drawing, in which- Fig.- 1 is a vertical section of my preferred form of coifee brewer;

Fig.- 2 is'an enlarged" vertical section of a slightly modified; form of stopper; and V,

Fig. 3 illustrates another form of stopper. For the purpose of illustration, the following description of my process and apparatus will be limited to the preparation of coilee but it is to be understood that thesame process and apparatus is equally adaptable to the preparation of other similar beverages.

Referring to Fig. 1, my Preferred form of cotlee brewer consists of a container H, which may be t 'in the form of a carafe or decanter, fitted with a stopper I! which contains a valve l3 com'.

prising a tubular valve body It, the lower portion of which is constricted, a valve plunger l5, operating within the valve body and seating itselfirrthe constricted portion thereof, a valve top it fitting firmly into, *or around, the valve body It in which is provided a port or "and an opening through which a valve stem I8 projects, and-a valve stem l8 connected to the valve plunger I5 and projecting beyond the valve body l4 through the valve top It by means of which the valve plunger may be manually raised from its seat to release a vacuum formed in the container I I. A longitudinal passageway l9 is provided through the stopper I2 in which the valve I3 is firmly positioned A handle 20 may be attached to the container for convenience in dispensing. c

The container ll may be of glass or other suitable material and is provided with a neck of suitable diameter, flaring outwardly at the lip to aid in pouring. It may be in the form of a carafe or decanterhaving a globe-like conltainer' portion and an elongated neck opening,

whereby the air is readily displaced by vapor and steam when heat is applied to the vessel, By means of this arrangement it is only necessaryto bring the water to a boil and'then remove the vessel from the source of heat. The vessel is sealed immediatelybefore it is removed, and i the brewing iseflected ,in a partial vacuum formed by the condensation of the vapor and steam. 1 The material of the container H should be moderately resistant to thermal shock and sufliciently strong to resist atmospheric pressure when the interior of the container is substantially below atmospheric pressure.

The stopper l2 fitsinto the neck of the container II with sufficient tightness to prevent' the leakage of air into the container and is preferably made of high-grade rubber compounded to resist oxidation and aging. One or more passageways l9 are provided through the stopper l2 connecting the interior of the concadmium or nickel, if desired, and is incorporated in the passageway l 9 where it is maintained normally' in its closed position, preferably by gravity. :When the stopper l2 is'placed in the neck of the container ii andjheat is applied to the container and its contents, the valve l3 operates to allow the release of the pressure developed within the container, as the pressure is transmitted through the passageway, l9 to the base of the valve plunger l5, forcing it, with its stem l8 upwards, thereby allowing the pressure to escape through the port or ports I'I. Thevalve l3 will assume a lower temperature than the escaping vapors due to its higher heat conductivity and exposure lowing:

to air, and therefore, acts as a condensor. The droplets of condensate remaining in the valve form a liquid seal when the valve assumes the closed position thereby eliminating the necessity of carefully machining the valve plunger and seat. When a vacuum is developed within the container II by the pressure of the atmosphere it forces the valve plunger l5 firmly into its seat, and so prevents the entrance of air into the container.- If desired, the outlet ports may be placed in the valve top I6, as shown in Fig. 1, rather than through the valve body. as shown in Fig. 2.

If desired, a stopper of the type illustrated in Fig. 3 may be used, in which case a passageway 2| is provided through the stopper 22 connecting the interior of the container II with the interior of the stopper cap 23, to which air has free ac cess through openings 24. A valve 25 is provided to seal the passageway 2| under normal conditions, but is capable of release, either manually, as by lifting the lugs or projections 26, or by an excess of pressure formed within the container The stopper cap 23 may be fastened to the stopper 22 in any desired manner, preferably by means of the inwardly extending flange portion 21 of the cap 23, on the inner side of which is provided projections or teeth 28 adapted to engage with corresponding indentations 29 properly positioned in the underside of an outwardly extending flange 30 of the stopper 22.

The valve 25 is held against the passageway 2| by means of springs 3| which may be integral with the valve. The action of these springs against the stopper cap 23 not only firmly seats the valve 25 against the passageway 2| but also serves to fasten the cap 23 more firmly to the stopper by forcing theprojections 28-into the corresponding indentations 29 on the underside of the stopper flange 3D. The portion of the valve 25 that seals the passageway 2| is preferably depressed somewhat below the normal plane of the valve to insure a more satisfactory seal. The

lugs 26 are a part of the valve 25 and extend through the openings 24 in the cap 23. By rais- 4 ing these lugs 26, or any one of them, the valve 25 is lifted from the passageway 2| and air is allowed free access to the interior of the container As a vacuum is developed within the container during my process, when this type of valve is used I prefer to constrict the passageway 2| at its upper terminal portion, as shown at 32, thereby facilitating the release of the valve 25 "and reducing the possibility of leakage.

Regardless of the type of valve used, I prefer to provide means for manually releasing the valve To prepare coffee in the apparatus described above, my improved method consists of/the fol- Place the desired amount of ground coffee beans in the container I, then add the proper amountof water, either hot or cold, but not to exceed 90 percent of the capacity of the container. Insert the stopper assembly in the neck of the container II and heat to boiling, then remove from the source of heat and ,allow to cool. The slight steam pressure so formedwithin the container forces the valve plunger |5 outwardly into the open position, allowing the air in the container 50 ticles.

and the vapors arisingfrom theheated solution to move through the peway ll into the interior of the valve I3 where at least a portion of the vapors are condensed, the excess escaping 5 through the port or ports When removed from the source of heat, the pressure within the container rapidly decreases to a point where it is insufficient to maintain the valve plunger I5 in its open position. When this point is reached, the

1 plunger l and stem l8 fall into the closed position on the valve seat in the constricted portion of the valve body I, and the condensate remaining in the valve forms a liquid seal over and around the valve plunger l5, effectively preventing the entrance of .air into the container. As

the container II and its contents cool, the pressure within the container is rapidly lowered below atmospheric due to the condensation of the steam. This reduced pressure incombination with the heat of the water brings the aromatic and flavoring substances in the ground coffee rapidly to the surface of the particles and into solution.

The container is maintainedin asealed condition forabout five minutes or until the action of the coffee particles has ceased. The vacuum is then released by raising the valve stem which opens thepassageway I9 into the container. As this equalizes the interior and exterior pressures,

30 the stopper may then be easily removed. When thevacuum is released any small coffee particles remaining suspended in the liquid will become saturated and immediately sink to the bottom, a strainer or filter not being needed, as all the coifee particles are completely saturated and will 4;) coffee is used.

As the precise reaction occurring during this process of extraction is not completely understood, I do not wish to be confined by any theory herein advanced, but for clarity of illustration 1' will explain the reaction to the best of my knowledge and belief. The aromatic and flavoring ingredients, which may be oil, esters, or other com-' pounds, are more or less water soluble materials held within the cells and body of the coffee par- To allow water to penetrate the interior cells and dissolve these. ingredients it is necessary to release in some manner the entrapped air.

, avithin the cells. The entrapped air is of course at normal at- 5 mospheric pressure, so unless some force is apwill by its own pressure move outwardly until the internal pressure balances the external. This action is augmented by the application of heat to the air within the cells. When the entrapped air has been released, the water may enter and e5 dissolve the desired aromatic and flavoring ingredients. P

Upon release of the vacuum the reverse of this process occurs, as the external pressure is then reater than that of the air remaining in the cells, so the water is-forced into the cells until the external and internal pressures are again equal. 5 The air drawn from the coffee particles' mayl contain certain vapors or other substances im-e, 76 parting flavor and aroma to the beverage. Any

ter while the air bubble is rising to the surface is retained in contact with the solution after release, as the container is closed. Likewise, any

dissolved ingredients volatilized by the heat or reduced pressure will condense upon the container 'walls above the liquid level and return to the solution by gravity.

Observation of my process tends to substantiate this theory, as the coffee particles may be observed to become covered with small air bubbles, rise to the surface where the bubbles are released, and then sink, repeating this operation several times until the particles apparently become completely saturated with water, when they sink to the bottom of the container, where they remain. Once the particles have settled to the bottom they cannot be re-suspended even by continued shaking.

From the-foregoing description, the advantages inherent to my process are more or less obvious. The parts are few in number and easily cleaned. Substantially all of the aromatic and flavoring substances in the cofiee are retained .as the container is sealed against their escape during practically the entire process. Furthermore, the minimum amount of beverage that may be prepared is not limited by the capacity of the container, as the cofiee and water are in direct'contact at all times. The harsh and unpleasant flavor sometimes present in cofiee that has been overboiled is not present, as the continued boiling which is necessary to extract these substances is neither necessary nor desirable in my process.

It is not necessary that the coffee be allowed to cool extensively as arelatively small drop in temperature produces 'a marked reduction in pressure; for example, as the liquid cools from 100 C. to 90 0., the pressure is reduced about 30% and if cooled further to 80 C. the pressure is reduced about 50%. When making large quantities of coffee, other methods of producing a vacuum may be used, such as an ordinary aspirator or vacuum pump connected to the upper part of,

the container or stopper in any desired manner, but this procedure is not as desirable for ordinary household use as that herein described due to the extra equipment required.

The foregoing description illustrates only the preferred embodiment of my process and apparatus which are obviously capable of considerable modification. In the process for example, the stopper may be inserted shortly before the container is removed from the source of heat, or the coffee particles may be added'after the water is heated, or .heated water may be added to the coffee particles. or the timerequired for the process may be reduced by rapidly cooling the container after the stopper has been inserted. The apparatus is also capable of wide variation as the shape of the container is not primarily important. The stopper may beused either with-or without 'a valve or valves, it being essential, however, that the stopper be constructed to produce an air tight 'seal across or within the neck of the container.

I do not theretore wish. to limit myself to the specific embodiment of my invention hereinbe fore disclosed except as defined by the appended claims.

I claim:

1. The process of brewing coffee or similar beverages comprising the steps of placing the material from which the flavoring substances are to be extracted in a container, adding water to the container, bringing the water to the boiling point, then sealing the container and allowing it to c001 without the application of any additional 5 heat.

2. The process of brewing coffee or similar beverages, comprising the steps of mixing ground coffee beans and water in a container, heating the mixture of ground coiiee beans and waterto boiling, exhausting steam and air until substantially all air is exhausted from the container, sealing the container allowing the container to cool without the addition of further heat, and then releasing the vacuum within the container whereby the ground cofiee beans become saturated with water and sink.

3. The process of brewing coffee or similar beverages, comprising the 'steps of partially filling a container with a mixture of ground cofiee beans and water, heating said mixture to a boil,

sealing the container, then without further addition of heat condensing steam within the container to produce a partial vacuum, and subsequently releasing said vacuum, the process being 26 characterized by the refluxing condenser action of the container walls on volatile coffee ingre dients vaporized while under partial vacuum.

4. The process of brewing coffee comprising the steps of mixing ground coffee with water in 30 a container, bringing the mixture of ground coffee and water to a boil and boiling just long enough to displace substantially all the air in the container with steam, sealing the container and immediately thereafter ceasing further appli- 85 cation of externa1 heat, then allowing the coffee .to brew under vacuum formed by the condensation of steam within the container for a period of approximately five minutes, and thenreleasing the vacuum. 40 5.-'I'he process of preparing coffee or similar beverages, wherein ground coffee is continuously immersed in water in a container having a restricted openingand the beverage ultimately separated from the grounds by decantation, said process being characterized by the use of external heat to bring the water to a boil, sealing the opening, and immediately thereafter brewing the coflee in said container without the application of additional heat.

which comprises mixing ground cofiee with water in a container having a small neck with an open I ing, applying heat to the container for heating the liquid and displacing the air in said conclosing said opening, brewing the coffee without the addition of further external heat, and finally releasing the vacuum.

7. A method of brewing coffee and the like,

which comprises mixing ground coffee with water in a container having a, small open passage, heating the container just long enough to cause the steam to displace the air in the container, and

then removing the container from the fire and closing the passage, then permitting the coffee MARSHALL N. STATES.

. 6. A method of brewing cofiee and the like,

tainer with steam, sealingsaid container by 

